390 Frame swop?

Hey everyone, I want to put my 1979 OR390 into a CR`77 -`78 frame, is this possible? can I use forks and rear shocks from my `79?

Thanks!!!

You would need to convert the triples to ball and cone or find someone to make you a set of Timken cups for the steering stem. Or come up with a 1977CR triple clamp set. The shocks may be a little too long for the ML frame but I have seen 16" Gas Curnutts on them.

Thanks for that info, think it be easier if I wait for a `79 frame to come along. How much does the steering improve between CR and OR as far as turning in quicker?

The main benefit you would get from the ML frame is sharper turning. 29° rake for 77 CR and later ML frame vs 30.5 rake for 1978 OR and all 1979 MM frames. I have a collection of ML frames for a few selected builds I am doing. Just for that tighter rake angle. I will check to see if I still have a ball and cone offset 35mm triple set left. I sold one and I likely still have one on hand

I can possibly make your Curnutts shorter to fit the earlier frame. The 78 OR had 16" Curnutts and the 79 had I believe16 3/4 inch shocks. I am too lazy to go out and measure a set but I can make the longer shock work.

Two things I forgot to mention is im running with 40mm forks , would make it more difficult to fit the earlier frame? also have a pair of recently refurbished ohlins fitted , id prefer to leave these as they are if it does not cause any issues?

You would still need Timken cups to use the 40mm front end on your frame. I got mine from harvesting from a trash 1978 ML frame. If not for that I would have had to make them. Unless you can adapt the triples to use the cones off the old triples. The stems I believe may be identical

Thank you for that Jim, just need to pick up a frame in the next few weeks, a winter project I think.
Cheers!

You may be able to convert the 40mm to ball and cone to get you thru. You have nothing to lose by trying anyway.